The aim of the proposed work is to discern the molecular systematics of one of the most specious families of coral reef fishes, the damselfishes (Pomacentridae), by continued expansion of a biochemical genetic data set that has been assembled at the University of Guam (UOG) Marine Laboratory. Specifically, it is anticipated that the proposed research will result in the accumulation of sufficient electrophoretic data necessary for the evaluation of the existing morphologically based classification of species, subgenera, and genera of Indo-Western Pacific damselfishes. An ancillary aim of the proposed work is to ensure that the UOG Marine Laboratory continues to support research in the burgeoning fields of biochemical and molecular genetics: achievement of this aim can only result in our enhanced ability to offer graduate and undergraduate training in molecular biology to students intending to pursue careers in the life sciences and health professions. It is anticipated that the proposed plan of research will expand substantially the data base which resulted from our prior electrophoretic surveys of the damselfish genera Pomacentrus, Stegastes, and Chrysiptera. Electrophoretic data from additional representatives of these three genera will be added to the data base and used in the construction of evolutionary trees by either frequency- or parsimony- based analyses. Genetically inferred phylogenies will then be compared with the existing morphologic systematic scheme for these taxa. The significance of the proposed study is that, if seen to fruition, it would: 1) validate the application of molecular biological techniques to an area of reef fish research that is crucial, given that coral reef communities are becoming imperiled at an alarming rate by the effects of human activities and; 2) provide much needed opportunities for student training in molecular biological techniques.